I’ve tried a couple of different ones but the one that stands out in my mind the most are the Shakeology drinks. They’re utterly disgusting no matter what you add to them and they cost a fortune (about $4 each) by the time you’re done shelling out. I think they work by making people unable to afford groceries lol.
Your best bet is to forgo the diet shakes and just preplan meals and snacks. Most of them work (short term) and as soon as you stop buying them or consuming them the weight packs right back on.